1. Combine all marinade ingredients in a blender and process to a smooth paste, adding 3-4 tablespoons of water if necessary for desired consistency (this can also be made in a large mortar and pestle for authenticity)
2. In a large baking pan or bowl, rub the pork all over with the paste and the citrus juice, pressing the mixture into the meat. Cover and refrigerate overnight.
3. Roasting: preheat oven to 325F. In a large Dutch oven or braiser, arrange the banana leaf to cover the bottom and sides of the pot, with enough to cover the top of the meat. Slice the onion. Place the meat and its juices into the pot on top of the leaves and add the onion and additional salt. Cover w the leaves. Pour stock into the pot and bring to a boil over medium heat. Cover the pot w a lid or foil and cook in the oven for 3.5-4 hours, periodically checking the liquid.
4. To serve, remove the meat from the pot, discarding the banana leaves. Carefully shred the meat. Take the remaining liquid and onions from the pot and process in a blender until smooth. Add the sauce back to the pork and toss to moisten. Serve w tortillas, pickled red onions, habanero salsa, and chopped cilantro.
PICKLED RED ONIONS
Peel and slice two red onions thinly, with the grain. Blanch the onions in salted water for 30 seconds then drain and rinse under cool water. Add 1/2 teaspoon black pepper, 1/2 teaspoon cumin, 1 teaspoon Mexican oregano, and 1 cup distilled white vinegar to a small container. Pass the onions and cover with water. Stir and let stand until onions turn pink, about 2 hours.
Take 12 habanero chilies and heat them in a sauté pan until color begins to develop. When chilies begin to color, transfer them to a blender and add 1/3 cup fresh squeezed lime juice and a pinch of salt.